1. Field of the Invention
This invention generally relates to a bicycle generator hub. More specifically, the present invention relates to a bicycle generator hub that rotatably mounts a wheel to a bicycle frame and generates power via the rotation of the wheel.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving various components of the bicycle. One component that has been extensively redesigned is the bicycle hub.
In general, a bicycle hub has an axle or a hub shaft that is detachably and non-rotatably mounted to a bicycle frame. A cylindrical hub shell is rotatably mounted to the hub shaft. Bearings rotatably support the hub shell around the hub shaft. The hub shell is connected to the rim of the wheel by spokes.
A bicycle hub having the above construction and a generator mechanism with a power source incorporated into the hub shell is known in the conventional art (See, Japanese Laid-Open Publication No. H09-132185). In the bicycle generator hub of the prior art, the generator mechanism is placed between the hub shaft and the hub shell. Specifically, a coil is non-rotatably mounted to the hub shaft and magnets are mounted to the inner circumferential surface of the hub shell. The hub shell is used as a yoke that serves as a magnetic path for the magnets. In order to reduce costs, the hub shell is made of iron.
The magnets and coil are surrounded by a magnetic member in that the magnetic iron hub shell also serves as a yoke. Therefore, it is difficult for a magnetic flux, which is generated by the magnets, to become concentrated in the coil. This reduces the power generation efficiency.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle generator hub that facilitates the concentration of the magnetic flux in the coil. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.